Revert "create PEP508 compliant dependency string for directory and file dependencies (#1796)" (#1865)

This reverts commit 10e471a0.

* fix (directory_dependency, file_dependency): create PEP508 compliant dependency string for directory and file dependencies

* fix (directory_dependency, file_dependency): making isort and black happy

* change (env.py): force recreation of venv if it is not sane

* new (env): add warning when forcing recreation

* fix (env): warning about broken venv placed right before calling recreation

* Update poetry/utils/env.py

Co-Authored-By: Sébastien Eustace <sebastien.eustace@gmail.com>

Co-authored-by: Sébastien Eustace <sebastien.eustace@gmail.com>

* fix(exporter): don't export local file dependency as editable

* fix(exporter): don't check for source_type "url" when prepending `-e`

Update CONTRIBUTING.md

Update the contributing instructions to use python-poetry instead of sdispater as the repository namespace.

* Handle nested wildcards in package includes correctly. Fixes: #1379.

Use compat `Path`.

* Ensure that when building sdists, subpackages with Python files (but not necessarily an __init__.py file) will be included.

* fix: removed hint for uninstall poetry, after installation.

* change (get-poetry.py): changed hint about uninstalling poetry

* fix (get-poetry.py): typo

* Fix PEP440 compatible release (`~=`) handling

PEP440 compatible release version range (`~=`) should have itself as a minimum
value. Examples from [official
doc](https://python.org/dev/peps/pep-0440/#compatible-release) (each pair is
equivalent):

```
~=2.2
>=2.2, ==2.*

~=1.4.5
>=1.4.5, ==1.4.*

~=2.2.post3
>=2.2.post3, ==2.*

~=1.4.5a4
>=1.4.5a4, ==1.4.*
```

In every case, lower bound is exactly same as the input version. Current
incorrect behavior was originally introduced 2 years ago by commit c55d55a8,
where it tried to reset patch version to 0 for tilde expression.

Closes #1150.

* Fix Black lint

Expand documentation of `git` dependency subkeys

I need to pin a dependency to a specific git commit hash. After reading
these docs, it was not clear to me that I could do so with the `rev`
key, because "something else" is vague. I wound up digging into the
source code and learned what I needed there.

This change expands the documentation for `git` dependencies to explain
the sub-keys in more detail and give examples of how to use each.

* Removing setecho(False) for all shells

* Only setecho(False) for zsh

* fix (setup_reader): in `setup.py` the `setup()` method can also be called by `setuptools.setup()`

* fix (setup_reader): make black happy

* fix (setup_reader): skip test for python <3.4

Fixed typo

Without this fix the helptext shows as:
```
  version                Shows the version of the project or bumps it when a validbump rule is provided.
```

Fix syntax errors in typehints

Fix simple typo: specificed -> specified

Closes #1753

Fixed default cache-dir path in docs.

Fixes #1735